Floor sanding machine



May 13, 1952 w. E. HOLT 2,596,689

FLOOR SANDING MACHINE Filed May 27, 1947 4 Sheets-Sheet 1 Summer z'am E170/15 Gttorneg May 13, 1952 w. E. HOLT 2,596,689

FLOOR SANDING MACHINE Filed May 27, 1947 4 Sheets-Sheet 2 c?) x Q 0 a Co Gttorneg May 13,1952 HOLT 2,596,689

FLOOR SANDING MACHINE Filed May 27, 1947 4 Sheeqs-Sheet 35 Imventor 7anon leg W. E. HOLT FLOOR SANDING MACHINE May 13, 1952 4 Sheets-Shaw's.4

Filed May 27, 1947 I Snventor 1U; [/z'amf 354% Gttomeg.

Patented May 13, 1952 FLOOR SANDING MACHINE- William E. Holt, Oakland,Calif.

Application May 27, 1947, Serial No. 750,845

4 Claims. (Cl. 51-176) This invention relates to the construction andoperation of floor sanding machines of the general type disclosed in *U.S. Patent 2,001,099 in which. a housing, enclosing a sanding drum at itsforward end and supporting an electric drive motor and blower fan, istiltable by the operator about a horizontal transverse axis forming theaxis of rotation of a pair of supporting wheels, to lower the sandingdrum to its operating position.

In-sanding machines of the type described, the electric drive motor isgenerally located on the top of the housing with its axis of rotationhorizontal and its center of gravity slightly forward of the verticalplane containing the axis of rotation of the pairof supporting wheelswhen the housing is in its horizontal traveling position, so that whenthe housing is tilted, or allowed to tilt, forwardly, the dead weight ofthe drive motor, which forms a substantial part of the weight of themachine, efiects' a substantial downward thrust on the sanding drumwhich is supplemented by a variable loading pressure exerted on the drumby the operator through the drum tilting mechanism, permitting a lightor heavy cut as floor conditions may require. The motor has driveconnections to the sanding drum and fan through separatebelt and pulleydrives. The power requirements for such service have resulted inthe useof sanding drums of relatively short transverse length, e. g. eightinches, due to limitations on motor size and weight in the particularmotor location described. Sanding drums "of greater length would requirean electric motor of greater horsepower having a larger diameter andgreater weight, resulting in a higher center of gravity for such amotor, whereby tilting of the machine housing would result in anexcessive dead loading of the sanding drum.

In accordance with the present invention, a sanding machine of the typedescribed is provided with an electric motor power capacity permittingthe use of a sanding drum of greater length, e. g. twelve inches,and'therefore correspondingly greater floor sanding capacity, whileretaining a motor weight distribution on the housing which will providea desirable loading pressure on the sanding drum when the housing istilted to the drum operating position. A further feature of theinvention is a drive motor mounting which permits the motor to bereadily detached from the housing to facilitate transportation of themachine. The improved motor mounting is used in conjunction with a belttightening mechanism for maintaining the belt drive connections to thesanding drum and fan in a efficient operating condition. A still furtherfeature of the invention is a supporting connection between the machinehousing and portable carriage which permits an adjustment of the housingabout itstilting axis to maintain the sandin surface of the drum inuniform contact throughout its length with the floor. Another feature ofthe invention is the provision of an auxiliary housing tilting mechanismfor exerting a variable resilient loading pressure on the sanding drum.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which is illustrated and described a preferred embodiment ofthe invention.

Of the drawings:

Fig. l is a perspective view of a floor sanding machine constructed inaccordance with'the invention; e i r Fig. 2 is an elevation of themachine shown in Fig. l with parts removed and cut away;

Fig. 31s a front end view of the machine;

Fig. 4 is a bottom view of the housing and supporting carriage;

Fig. 5 is a front view of a motor mount;

Fig. 6 is an end view of a motor mount Fig. 7 is a plan view of one ofthe belt adjusting rods;

Fig. 8 is a front view of the drum pulley;

Fig. 9 is a front view of the front motor pulleys;

Fig. 10 is a front view of the rear motor pulley on a different scale; v

Fig. 11 is a front view of the fan pulley;

Fig. 12 is a front view of the ratchet tension handle; and

Fig. 13 is a vertical section taken'on the line l3-l3 of Fig. 2.

The floor sanding machine illustrated comprises an elongated wheeledhousing 20 having a top plate 2! and depending vertical side plates 22and 23, the forward end of the housing being closed by aweightedangulardrum cover plate 24 hinged to the top plate. Atransversely elongated sanding drum 25 is journaled in the front portionof the side plates, with a drum axle projecting beyond the side plate 22and carrying a double drive pulley 26. The housing is tiltably mountedon a three-wheeled supporting carriage 30, as hereinafter described, thecarriage having an angle from its forward end extending the full housingwidth adjacent the lower part of the drum periphery to a point adjacentthe-rear end of the housing, as shown in Figs; 2 -and;4.

The rear portion of the duct opens through the top plate 2| to the inletof an exhaust ran '38 mounted on the top plate. The fan outlet connectswith a stationary 'vertical tube 39 which terminates in a swivel mountedgoose neck 49 'ongwhich'a dust bag 41 is supported, as indicated "inFig. 1. 'A removable clean out plate 42 is arranged in the bottom of theduct 39 below the fanto provide access to the fan inlet and duct.

,The 'spaced pairs of wheels 31 and 3-2 are rotatab'lyfmounted on theaxle 29,- one end of whichis shaped to fit into and through acountersu'nk opening 45 in the housing side plate 22 with sufiicientclearance to permit adjustment of theopposite end of the axle29 in thedesired range of movement. This end of the axle is positioned in anopening 44 in one leg 48 of a 'bell crank lever 41 which is mounted on athreaded portion of a bolt 49 passing through an unthreaded opening inthe housing side plate 23. With this construction the bolt 49 isloosened to permit angular adjustment of the lever 41 and tightened tohold the lever in its adjusted position. The other leg of the lever '41has "a transverse flange 59 with a'vertically elongated slot 5| throughwhich a threaded axle adjusting rod 52 extends. The rod 52 is held inthe slot by a fixed collar 53 and flat washer 54 at the rear side of theflange 59 and a flat'washer55,

felt or spring washer 56 and nut 51 at the front 'side of the flange.The-ro'd passes rearwardly through an unthreaded guide opening in theforward leg of a U-shaped bracket 59 secured on the side plate 23 and athreadedopening 69 in the other leg, terminating in a hand wheel 6|externally of'thehousing. A lo cknut 62 at the rear side of the rearbracket leg holds1the rod 52 in its' adjusted'position With thedescribed construction, the floating endfof the axle 29 can'be adjustedrelative to the housing to bring the s'and in'g'drum into uniformcontact with the floor throughout the drum length by first loosening thelockziut 62 and pivot bolt 49 and then adjustingithe rod 52 to arouatelyraise or lower the position of the bell crank lever opening 44carrying'the axle end. The felt or spring. Washer maintains a resilientcontact between the flange 59 and rod 52, while permitting relativemovement of the ro'd'and flange slot.. When the desired adjustment -hasbeen made; thebolt 49. and 'locknut 62 are tightened to lock the partsin the adjusted position. v

The housing is tiltable about the axis of the axle 29 to depress thesanding drum by means of a drum pressure lever 19 having a-forwardlyofiset handle portion 11 and pivotally mounted on one side of a bracketH surrounding the upper part. of the column 34. The-bracket ll hasatoolsocket 12J'andcarries aswingable coiled wire .;l;3 which acts as. apower. cable support..-

The lower end of the lever 10 is connected through a clevis 14 to a rodl5 Which is adjustable in length, having its lower end adjustablyconnected to a clevis l6 pivotally mounted on the rear end of thehousing top plate. The ofiset handle section of the lever 'HJ contactswith the handle 35 in the lever raised position illustrated, in whichposition the pivot connection of the rod 15. and clevis 14 is .beyondthe dead cent'erposition. The lever is moved forwardly to the dottedline position shown in Fig. 2 to allow the housing to tilt forwardlyabout the tilting axis and thereby depress the drum into contact withthe floor to be surfaced. Manual pressure on the lever 79 by theoperator correspondingly increases the drum pressure on the -fioo'rr H Apredetermined pressure is resiliently exerted and maintained on the drumwhen in use through a pair of links 89 hingedl y connected to therea'r'edge of the'hou'sin'g top pla'te 21 and having theirother'endsconnected to a common coiled spring '81. p The spring 81 is connected toa'ratchet'handle 82 pivoted on a bracket'BB secured onthe column 34 andcarrying a ratchet plate 84. The particular se'tting' of the pivotedhandle 82 in the notched'plate M'determinesthe tension on the spring 8|and thereby the pressure resiliently maintained on'th'e sanding drum. Inuse the lever 19 is first moved to allow the sanding drum to lower intocontact with the floor due to the weight distribution on the housing.The ratchet handle '82 is then adjusted to exert the desired resilientpressure onfthe drum. 'Any desired "additional loading pressure on thedrum is then exerted by the operator pressing forwardly on the lever 19.Arelativ-ely wide range of drum operating pressures' isthus attainable.7

In accordance with the invention, the power requirements of the machineare supplied by a pair of electric motors B6 and 8-? arranged 'intandem. The motors are mounted on the housing to'p'plate ashereinafterd'escribed withtheir axes-of rotation horizontal and alongwith their respective centers of gravity, at opposite sides of the'verticalplane containing the tilting axis, both when'tlie housing'is'inits traveling position and also inits drum operating position. 'lntlieembodiment illustrated, the motorsare -"of equal size and horsepower andarranged' so that the vector resultant of the combined m'ot'or weightsis 'slightly-torwa'rd of 'the'de's cri be'd vertical plane when thehousing is in the position shown-in "Fig. 2, s'o'that-the housingwilltil't forw'ardly'unv with the usual starting and changeover switchesand power connections to the motors and power source. n I

As illustrated, the shaft oithemotdrfBB oarries-a pair of doublepulleys- 99 and9l, the outer pulley being connectedto the-largerdiameter drumpulley -26 by a pairof belts '92. Theinner pulley 9i isconnected to-a sim'ilar sizedouole pulley 93 on'the shaftpf themotor'8lby belts '94. This shaft also carries a larger innerpulley 95which :is' connected by a belt 96*to a' smaller .tors to the sandingdrum and fan. As shown in Fig. 1, the drive pulleys and belts areenclosed by a guard member 99 which is detachably connected to thehousing.

In accordance with the invention, the motors 86 and 81 are mounted in amanner to permit the various belts to be readily adjusted as totightness and the motors to be quickly detached from the machine tofacilitate its transportation. For this purpose a flattened U-shapedbracket Hill is transversely secured tothe housing top plate rearwardlyof each motor, and as shown in Figs. 2, 5 and 6, a flattened U-shapedmotor support cradle I! is pivotally mounted on a removable rod I02which extends through the pairs of end flanges of the bracket andcradle. Each motor casing is secured to the corresponding cradle. sothat each motor and cradle can be arcuately moved on the rod M2 toadjust the associated drive belts. The mechanism for this purposeconsists of a threaded rod I05 having its rear end pivotally connectedto a bracket 35 mounted on the upper side of the motor 81, as shown inFig. 7. The forward end of the rod extends through a bracket IE6 securedon the top of the motor 86. A hand wheel I0! is then threaded on theprojecting end of the rod and is manually adjusted to tilt the motor 86about its supporting rod I62, and thus regulate the tension of the belts92. .A second adjusting rod IDS is vertically arranged between themotors with its lower end in contact with the housing top plate andthreaded through a bracket I09 fixed to the lower part of the motor 81.The rod extends through a guide opening in the motor bracket I05 andcarries a hand wheel H0 at its upper end. Movement of the handwheel H0tilts the motor 81 about its supporting rod [02 to regulate the tensionon the belts 96. The drive belt 94 to the fan is adjusted by anadjustable idler roll H2 in a well known manner. The belt adjustingdevices are successively regulated to provide the desired tension in thevarious drive connections. The mounting of the motors 86 and 81facilitates this adjustment.

The sanding machine illustrated is designed to permit its transportationbodily by one man by a relatively simple disassembly of the motors anddrive belts by withdrawing the motor support rods I02, disconnecting andseparately carrying the motors 8'6 and 81. Transportation of the machineis also facilitated by a U-shaped tubular pull-out handle H5 slideablymounted in brackets H6 on the forward part of the housing top plate andnormally held therein by set screws Hi. The handle is extended to itsforward position when two men are available to carry the machine andreturned to its retracted position when the machine is to be put intoservice, permitting the drum cover plate 24 to be then raised for accessto the drum.

While in accordance with the provisions of the statutes, the best formof the invention known has been disclosed, those skilled in the art willunderstand that changes may be made without departing from the spirit ofthe invention covered by the claims, and that certain features of theinvention may sometimes be used to advantage without a corresponding useof other features.

I claim:

1. A floor surfacing machine comprising a, supporting carriage, ahousing tiltably mounted on d said carriage about a transverse axis, asanding drum rotatably mounted'in the forward end of said housing,meansfor controlling'the tilting of said housing, an exhaust fan on saidhousing having a vacuum connection to saidsandin drum, and drive meansfor said sanding drum and fan including a pair of electric motorsmounted in tandem on said housing with their drive shafts arrangedtransversely of said housing and with their centers of gravity arrangedat opposite sides of the vertical plane containing the tilting axis ofsaid housing and the vector resultant of their combined tilting effectsrelative to said tilting axis being located forwardly of said verticalplane when the housing is in an untilted position, and endless beltsforming drive connections between said motors and between said motorsand said sanding drum and fan.

2. A floor surfacing machine comprising a supporting carriage, a housingtiltably mounted on said carriage about a transverse axis, a sandingdrum rotatably mounted in the forward end of said housing, means forcontrolling the tilting of said housing, an exhaust fan on said housinghaving a vacuum connection to said sanding drum, drive means for saidsanding drum and fan including a pair of electric motors mounted on saidhousing with their drive shafts arranged transversely of said housingand with their centers of gravity arranged at opposite sides of thevertical plane containing the tilting axis of said housing and thevector resultant of their combined tilting effects relative to saidtilting axis being located forwardly of said vertical plane when thehousing is in an untilted position, endless belts forming driveconnections between said motors and between said motors and said sandingdrum and fan, and means for detachably supporting each of said motors onsaidhousing.

3. A floor surfacing machine comprising a supporting carriage having atransverse axle at its forward end, a pair of transversely spacedsupporting wheels on said axle, an elongated housing having dependingside plates and a sanding drum rotatably mounted in the forward end ofsaid side plates, means for tiltably mounting said housing on saidsupporting carriage comprising a housing side plate arranged to supportone end of said axle, a bell crank lever pivotally mounted on theopposite side plate and having an arcuately movable lever arm supportingthe opposite end of said axle, an axle-adjusting screw horizontallymounted in said housing and having a connection with the other arm ofsaid lever permitting relative movement of said parts, means at the rearof said housing for operating said adjusting screw, and means forlooking said adjusting screw and said lever in their adjusted positions.

4. A floor surfacing machine comprising a supporting carriage having atransverse axle at its forward end, a pair of transversely spacedsupporting wheels on said axle, an elongated housing having dependingside plates and a sanding drum rotatably mounted in the forward end ofsaid side plates, means for tiltably mounting said housing on saidsupporting carriage comprising a housing side plate arranged to supportone end of said axle, a bell crank lever pivotally mounted on theopposite side plate and having an arcuate- 1y movable lever armsupporting the opposite end of said axle, an axle-adjusting screwhorizontally mounted in said housing and having a connection with theother arm of said lever per-

